Repairing Copper Pipe

Because of its durability, copper is the preferred material for most water supply lines. However, copper pipe can leak when dented, punctured, or weakened from corrosion. Joints can degrade too.

Even if you have galvanized or plastic supply pipe in your house, you may want to use a transition fitting and switch to copper when making a repair or extending a line. When joining copper pipe to steel pipe, be sure to use a dielectric fitting to avoid corrosion.

Rigid copper joints are soldered together. The resulting joints, if made correctly, are at least as strong as the pipe itself. To add a supply line, install a tee fitting. Use a compression fitting only if it will remain exposed for inspection.

Step 1

Shut off the water. Use a tubing cutter to cut on each side of the damaged area. Screw the cutter tight, rotate it a full turn, tighten, and rotate again until the cut is complete. If there is not enough room, cut with a hacksaw. Exert gentle pressure to avoid flattening the pipe. File off burrs.

Compression fittings often make sense in tight places where it is difficult to solder. To install one, slide the nut, then the ferrule, onto the pipe. Slip the fitting onto the pipe, slide the ferrule into the fitting, and tighten the nut. No thread tape or pipe compound is necessary.

Step 2

If either of the existing pipes is movable, you can use standard couplings. If not, use slip couplings (Step 3). Measure the replacement piece by holding it in place. It should be the same length. Cut the new piece with a tubing cutter.

While not as fail-safe as a sweated patch, fiberglass patch tape can provide a quick, long-lasting cure for a leaky pipe. The kit includes tape impregnated with resin, gloves, and a lubricant that helps you squeeze out voids and bubbles.

Step 3

Ream and polish the pipe and couplings using a multiuse brush. Brush on flux and slide a coupling on each side, position the replacement piece, and slide the couplings back halfway. (To install a standard coupling or elbow, give it a slight twist as you push it all the way into place.)

Protect framing and nearby walls with a cookie sheet or fiber shield. Aim the torch so the tip of the blue flame touches the middle of the fitting. When the flux sizzles after 5 seconds or so, move the flame to the opposite side and heat it briefly. Touch solder to the joints.

Once solder has been sucked into the joint all around, wipe the joint with a rag to smooth the solder and eliminate any drips. Fold the rag several times and/or wear leather gloves. Repeat for the other side of the fitting. Check the work area an hour later to be sure nothing is smoldering.